The largest unreinforced concrete dome ever built. It is 1,900 years old.
€5 timed ticket30-45 min
The story
1 min readAD 126, Hadrian. The 43.3 m dome has never been surpassed in unreinforced concrete: walls grade from 6 m thick to 1.2 m at the crown, the aggregate lightens with height from travertine to volcanic pumice, the coffers cut dead weight, and the 8.2 m oculus is open to the sky (the floor drains handle rain).
Brunelleschi studied it before daring the Florence dome; every dome of your week is a reply to this room. Raphael is buried here at his own request.
The shot
The light shaft from the edge of the rotunda; on the way, the gran caffè at Sant'Eustachio (since 1938) is the best coffee in Rome.